Different Trajectories of Apathy and Depression Among Subjective Cognitive Impairment Individuals with or without Conversion to Dementia: Results from the Memento Cohort in France

BACKGROUND

Apathy and depression are two early behavioral symptoms in Alzheimer's disease (AD) and related disorders that often occur prior to the onset of cognitive decline and memory disturbances. Both have been associated with an increased risk of conversion to dementia, with a distinct neuropathology.

OBJECTIVE

The assessment of the trajectories of apathy and depression and their independent impact on dementia conversion.

METHODS

Apathy and Depression were measured using the Neuropsychiatric Inventory for caregiver (NPI) and clinician (NPI-C), among the nondemented individuals reporting subjective cognitive decline (SCD) at baseline. They were followed up over a 60-month period. Some converted to dementia, according to the methodology carried out by the French Memento Cohort.

RESULTS

Among individuals with SCD (n = 2,323), the levels of apathy and depression were low and did not evolve significantly over the 60-month period, despite a trend in apathy increasing as of month 24. Regarding SCD individuals who converted to dementia within the 60-month period (n = 27), the prevalence of depression remained globally steady, while the levels of apathy increased over time.

CONCLUSION

Apathy and depression have different trajectories among individuals with SCD and apathy alone is more likely-compared to depression-to be associated with conversion to dementia.

How many patients are eligible for disease-modifying treatment in Alzheimer's disease? A French national observational study over 5 years

OBJECTIVE

We aimed to study the epidemiology of the prodromal and mild stages of Alzheimer's disease (AD) patients who are eligible for clinical trials with disease-modifying therapies.

SETTINGS

We analysed two large complementary databases to study the incidence and characteristics of this population on a nationwide scope in France from 2014 to 2018. The National Alzheimer Database contains data from 357 memory centres and 90 private neurologists. Data from 2014 to 2018 have been analysed.

PARTICIPANTS

Patients, 50-85 years old, diagnosed with AD who had an Mini-Mental State Exam (MMSE) score of ≥20 were included. We excluded patients with mixed and non-AD neurocognitive disorders.

PRIMARY OUTCOME MEASURE

Descriptive statistics of the population of interest was the primary measure.

RESULTS

In the National Alzheimer Database, 550 198 patients were assessed. Among them, 72 174 (13.1%) were diagnosed with AD and had an MMSE ≥20. Using corrections for specificity of clinical diagnosis of AD, we estimated that about 50 000 (9.1%) had a prodromal or mild AD. In the combined electronic clinical records database of 11 French expert memory centres, a diagnosis of prodromal or mild AD, certified by the use of cerebrospinal fluid AD biomarkers, could be established in 195 (1.3%) out of 14 596 patients.

CONCLUSIONS

AD was not frequently diagnosed at a prodromal or mild dementia stage in France in 2014 to 2018. Diagnosis rarely relied on a pathophysiological marker even in expert memory centres. National databases will be valuable to monitor early stage AD diagnosis efficacy in memory centres when a disease-modifying treatment becomes available.

Dysexecutive disorders and their diagnosis: A position paper

Although executive function disorders are among the most prevalent cognitive impairments a consensus on diagnostic criteria has yet to be reached. With a view to harmonizing these criteria, the present position paper (i) focuses on the main dysexecutive disorders, (ii) examines recent approaches in both the behavioral and cognitive domains, (iii) defines diagnostic boundaries for frontal syndrome, (iv) reports on the frequency and profile of the executive function disorders observed in the main brain diseases, and (v) proposes an operationalization of diagnostic criteria. Future work must define the executive processes involved in human adaptive behavior, characterize their impairment in brain diseases, and improve the management of these conditions (including remediation strategies and rehabilitation).

Author Correction: Pathogenic p62/SQSTM1 mutations impair energy metabolism through limitation of mitochondrial substrates

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Efficacy of Transcranial Direct Current Stimulation Combined with Cognitive Training in the Treatment of Apathy in Patients with Alzheimer's Disease: Study Protocol for a Randomized Trial

BACKGROUND

Apathy, commonly defined as the loss of motivation, is a symptom frequently encountered in Alzheimer's Disease (AD). The treatment of apathy remains challenging in the absence of any truly effective medications. Transcranial Magnetic Stimulation (rTMS) or Transcranial Direct Current Stimulation (tDCS) can improve cognitive disorders, but do not appear to improve apathy. Isolated cognitive training also appears to have no effect on apathy. We propose to test the efficacy of a new procedure for the treatment of apathy in AD patients consisting of a combination of tDCS and cognitive training, based on the latest guidelines for the design of therapeutic trials in this field.

METHODS/DESIGN

This article primarily describes the design of a monocentre, randomized, doubleblind trial to be conducted in France to evaluate the effect of the combination of tDCS and cognitive training on apathy compared to a group treated exclusively by cognitive training (sham tDCS). Twenty- four patients under the age of 90 years with mild-to-moderate Alzheimer's disease (Mini Mental State Examination score between 15 and 26/30) (MMSE)) presenting clinically significant apathy evaluated by the Apathy Inventory (AI) and the NeuroPsychiatric Inventory (NPI) apathy subscore will be enrolled. Severe depression will be excluded by using the NPI depression subscore. Treatment will comprise 10 sessions (D0-D11) including tDCS (bilateral prefrontal, temporal and parietal targets) and Cognitive Training (Cog) (6 simple tasks involving working memory, language and visuospatial function). After randomization (ratio 2:1), 16 patients will receive the complete treatment comprising tDCS and Cog (group 1) and 8 patients will be treated exclusively by Cog (sham tDCS) (group 2). The primary endpoint will be a significant improvement of the AI score by comparing baseline measures (D-15) to those recorded one month after stopping treatment (D44). Secondary endpoints will be an improvement of this score immediately after treatment (D14), 2 weeks (D29) and 2 months (D74) after stopping treatment and improvement of the MMSE score, NPI apathy subscore, ADAS Cog (Alzheimer Disease Assessment cognitive Scale subsection), ADCS-ADL (Alzheimer Disease Cooperative Study-Activities of Daily Living), FAB (Frontal Assessment Battery) and the latency of P300 evoked potentials at the same timepoints.

CONCLUSION

The purpose of our study is to check the assumption of tDCS and cognitive training efficacy in the treatment of apathy encountered in AD patients and we will discuss its effect over time.

Pathogenic p62/SQSTM1 mutations impair energy metabolism through limitation of mitochondrial substrates

Abnormal mitochondrial function has been found in patients with frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Mutations in the p62 gene (also known as SQSTM1) which encodes the p62 protein have been reported in both disorders supporting the idea of an ALS/FTD continuum. In this work the role of p62 in energy metabolism was studied in fibroblasts from FTD patients carrying two independent pathogenic mutations in the p62 gene, and in a p62-knock-down (p62 KD) human dopaminergic neuroblastoma cell line (SH-SY5Y). We found that p62 deficiency is associated with inhibited complex I mitochondrial respiration due to lack of NADH for the electron transport chain. This deficiency was also associated with increased levels of NADPH reflecting a higher activation of pentose phosphate pathway as this is accompanied with higher cytosolic reduced glutathione (GSH) levels. Complex I inhibition resulted in lower mitochondrial membrane potential and higher cytosolic ROS production. Pharmacological activation of transcription factor Nrf2 increased mitochondrial NADH levels and restored mitochondrial membrane potential in p62-deficient cells. Our results suggest that the phenotype is caused by a loss-of-function effect, because similar alterations were found both in the mutant fibroblasts and the p62 KD model. These findings highlight the implication of energy metabolism in pathophysiological events associated with p62 deficiency.

APP, PSEN1, and PSEN2 mutations in early-onset Alzheimer disease: A genetic screening study of familial and sporadic cases

BACKGROUND

Amyloid protein precursor (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2) mutations cause autosomal dominant forms of early-onset Alzheimer disease (AD-EOAD). Although these genes were identified in the 1990s, variant classification remains a challenge, highlighting the need to colligate mutations from large series.

METHODS AND FINDINGS

We report here a novel update (2012-2016) of the genetic screening of the large AD-EOAD series ascertained across 28 French hospitals from 1993 onwards, bringing the total number of families with identified mutations to n = 170. Families were included when at least two first-degree relatives suffered from early-onset Alzheimer disease (EOAD) with an age of onset (AOO) ≤65 y in two generations. Furthermore, we also screened 129 sporadic cases of Alzheimer disease with an AOO below age 51 (44% males, mean AOO = 45 ± 2 y). APP, PSEN1, or PSEN2 mutations were identified in 53 novel AD-EOAD families. Of the 129 sporadic cases screened, 17 carried a PSEN1 mutation and 1 carried an APP duplication (13%). Parental DNA was available for 10 sporadic mutation carriers, allowing us to show that the mutation had occurred de novo in each case. Thirteen mutations (12 in PSEN1 and 1 in PSEN2) identified either in familial or in sporadic cases were previously unreported. Of the 53 mutation carriers with available cerebrospinal fluid (CSF) biomarkers, 46 (87%) had all three CSF biomarkers-total tau protein (Tau), phospho-tau protein (P-Tau), and amyloid β (Aβ)42-in abnormal ranges. No mutation carrier had the three biomarkers in normal ranges. One limitation of this study is the absence of functional assessment of the possibly and probably pathogenic variants, which should help their classification.

CONCLUSIONS

Our findings suggest that a nonnegligible fraction of PSEN1 mutations occurs de novo, which is of high importance for genetic counseling, as PSEN1 mutational screening is currently performed in familial cases only. Among the 90 distinct mutations found in the whole sample of families and isolated cases, definite pathogenicity is currently established for only 77%, emphasizing the need to pursue the effort to classify variants.